DESCRIPTION (Description as provided by applicant): Stroke is the leading cause of adult disability in the United States, making it a major public health concern (1). The Centers for Disease Control (CDC) estimates the annual cost of stroke in the United States to be $36.5 billion (1). Accordingly, it is clear that the negative personal and societal impact of stroke is vry high. Stroke is typically thought to affect older persons; however, many younger individuals also suffer strokes. For example, at least half of all stroke patients in the state of South Carolina ar under the age of 60 (2). Approximately a quarter of all chronic stroke survivors present with aphasia, a language disorder caused by damage to the speech and language areas of the brain (3, 4). The prevalence of chronic aphasia in the United States is estimated to be one million. Aphasia can vary in severity from very profound impairment that renders patients mute and without the ability to understand others' speech, to milder forms where patients have great difficulty retrieving specific words. In the chronic stage of stroke, aphasia has been identified a the strongest predictor of poor quality of life. Aphasia not only influences the ability to communicate with family and friends, but also drastically decreases education and employment opportunities. Although some degree of spontaneous recovery from aphasia is typical in the first weeks and months following stroke, many patients are left with devastating communication problems. Once aphasia has become a chronic condition, the only road to recovery is through aphasia therapy. Several meta-analysis studies suggest that aphasia therapy is effective. In spite of decades of research, very little is known about which patients benefit the most from treatment and what kind of treatment should be administered to patients with different impairment profiles. The overarching goal of the research proposed here is to improve aphasia treatment effectiveness as well as identify patient factors that can be used to improve diagnosis of language impairment, guide aphasia treatment, and predict prognosis. Specifically, the focus of our center (Center for the Study of Aphasia Recovery; C-STAR) is to examine the extent to which factors such as behavioral aphasia treatment, electrical brain stimulation, and residual brain function influence aphasia recovery. To accomplish our research goals, this project will rely on collaboration among four main investigators: Drs. Julius Fridriksson, Argye Hillis, Chris Rorden, and Greg Hickok. Projects led by Fridriksson (chronic patients) and Hillis (acute patients) will focus on factors that may promote improved outcome of aphasia therapy. Both projects will yield a vast, unique dataset including measures of brain status and response to aphasia treatment. Relying on this dataset, Rorden's project will predict recovery from aphasia using machine learning approaches whereas Hickok will utilize the same data to better understand aphasic impairment in relation to contemporary models of speech and language processing.